ptatohed

iTrader: (12)

I have never had a problem before but here were my numbers:

HC (PPm) at 15mph:
Maximum = 54, Average = 12, Measured = 54

CO (%) at 15 mph:
Maximum = 0.50, Average = 0.05, Measured = 0.09

NO (PPM) at 15 mph:
Maximum = 992, Average = 74, Measured = 261


They repeat the above measurements at 25mph but those were better than these.
As you can see,I am higher than average in all three catagories. But
what's scary is that 54 I got of HC! One more and I wouldn't have passed.
I don't know why. I did fine last time, I was around average for
all. I baby my car and do all the preventative maintenance and it's running great.
The only difference that I can even think of is the G-Force ECU.
Could that be it? I'm real worried I won't pass next time. My car
won't be getting any younger! Any advice?

Thanks guys.

P.s. What is 'HC'? Hydro Carbon?

mzmtg

iTrader: (11)

Yes, HC is hyrrocarbon. It is a measure of unburned fuel in the exhaust stream.

Did you do a complete warm up? By this, did you drive around for at least 45 min to get everything nice and hot? This can make a big difference.

BEJAY1

iTrader: (19)

Like mzmtg said you need at least 30+min warmup - hwy speeds. That's most important at the lower test speeds.

If the HC is 5x higher than the passing level then that usually means a problem with the CatConv not burning off unspent fuel. If your '96 has an OB2 connector than try scanning for errors. If your ECU and S/C changes allow it.

Anybody else know about high HC with S/C?

P.S. I pulled out my G-force for my tests just in case. I dropped $800 in parts & tests before I passed. Turned out my engine was running rich and I blew my RT Cat. MIL didn't tell me there was a problem.

ptatohed

iTrader: (12)

Thanks guys. No, SuperCharger isn't installed yet so that can't be an issue.

I guess I could have warmed it up more. I got there 45 minutes before my appt. and waited. ??

Thanks guys.

SuDZ

Was it running while you were waiting?

SuDZ

ptatohed

iTrader: (12)

No, that's what I was saying. You guys said to have it warmed up and I was pointing out I got there early so my car sat for 45-50 minutes. Would I really have had better numbers if I went there with the car warm?

SuDZ

Most likely because then the car has been running and basicly cleared its throat. As compared to when it first starts it idles higher and will run a tad bit rougher. So it gives out more exhaust etc.

SuDZ

Gotrice4

Weird thing happened to me when i got smogged last month...i warmed up my car thoroughly by driving first easy then went to highway driving for over a half an hour...then i went to the waiting lines and kept the engine on...then they told me to shut off the car right b4 they put the thing on the dyno...then they restarted it and right onto the dyno for the test...it surprised me cuz i thought, well didn't that sort of defeat the purpose of me warming up my car? I mean i passed with flying colors but that sort of surprised me and worried me b/c my car was on the dyno for at least 15 minutes....I live in Illinois....

SuDZ

How long did they leave it off for? If only a minute or two it wouldnt really hurt ya that much. Mainly it is when it hasnt been started over night or whatever that causes more of a problem.

SuDZ

mzmtg

iTrader: (11)

nah, you were still plenty hot after being shut off for only a few minutes. Shutting off for 45 minutes will allow too much cooling however. HC is what really goes up on a cold cat. this is why manufacturers are mounting the cats closer and closer the the exhaust ports. It speeds up cat "light off" immensely. Hell, the WRX has a cat before the turbo.

BEJAY1

iTrader: (19)

Just be thankful you passed. Took me 5+ trips to the stupid dyno's to pass. Glad they're not gonna require the dyno's in IL for 96+ cards.

Sexima

do you have a y pipe?

ptatohed

iTrader: (12)

So what was the conclusion guys? What can I do to make 100% sure I pass next time (2 years from now)? Besides let her warm up.

The difference will be a SC, perhaps a Y-Pipe and ... ? ... not sure right now.

Thanks for the input/advice.